1. Field of the Invention
The present invention relates to body structures for single lens reflex (SLR) cameras.
2. Description of the Related Art
It is well known that the structure of single lens reflex cameras is such that to observe a photographic image which has been imaged on a viewfinder image plane, the position of the viewfinder image plane must be adjusted to be in conjugate relation to a film surface. For this purpose, prior art single lens reflex cameras used screws to adjustably and fixedly mount a member which included a viewfinder screen to the body of the camera. A floating or adjustable setting was achieved by means of springs and the like which were set in place by screws. In this way, the screws were manipulated to adjust the amount of compression relative to the body, so as to adjust the position of the viewfinder screen.
The above-mentioned camera bodies, however, required difficult adjustment procedures and apparatuses which were costly to manufacture and difficult to use. Such deficiencies of the prior art are solved by the present invention.
In addition to the problems associated with providing a viewfinder imaging plane that is mounted on a camera body in such a manner that the viewfinder image plane is in conjugate relation to a film surface, there are other problems associated with a camera body having multiple parts.
Such other problems are illustrated in FIG. 5, wherein a camera body is shown as being comprised of at least two parts (i.e., a front part and rear part which are not formed together).
Typically, such multi-part camera bodies are configured so that the shutter 106 is mounted on the rear body 103, and a mirror box (not shown in the drawing) is mounted on the front body 104. Next, the front body 104 is affixed to a mounting surface 103a of the rear body 103, and furthermore a mount 105 is affixed to the front body 104.
The surface of the mount 105 (right-hand lower side of FIG. 5) consists of a standard surface for the installation of a photographic lens. Moreover, a rail surface or system 108 for the travel of the photographic film is arranged on the back surface (left-hand upper side of FIG. 5) of the rear body 103. The front body 104 is interposed between mount 105 and the rear body 103.
Referring now to FIG. 6, therein depicted is a cross section of the front body 104 in the mounted state on the mounting surface 103a of the rear body 103. Between the mounting surface 103a and the mounting surface of the front body 104, a gap normally results because shaping and forming of the front and rear halves of the body is difficult and not exact. In such a state, when screw 107 is tightened, the gap between the mounting surface 103a and the mounting surface of the front body 104 is small, and deformation as shown in FIG. 6 arises, with the result that the front body 104 deforms. Due to the deformation of the front body 104, a change of the position of the mount surface of the front body 104 results.
As such, due to the tightening intensity of screw 107, there is a change in the distance between the mount surface and the rail surface on which the photographic film travels. Accordingly, after repairs and the like, in the case in which the rear body 103 and the front body 104 are mounted and reassembled together, it becomes necessary to readjust the distance between the mount surface and the rail surface on which the photographic film travels. Plastic, multi-part camera bodies are even more susceptible to the problems addressed here.
Even if changes are made to the assembly of the photographic lens and the body, it is normally necessary, so as to be able to focus accurately on the photographic film surface, to fix the distance between the mount surface and the rail surface on which the photographic film travels. As such, it is also necessary for the scatter of the distance between the mount surface and rail surface to be small.
Accordingly, because the front body 104 is interposed between mount 105 and rear body 103, a problem arises in that the distance between the mount surface and the rail surface on which the photographic film travels is not constant and is often large. More particularly, the problem mentioned here is due to the interposition of the front body 104, the dimensional scatter of the front body 104, and the deformation of the front body 104 when the front body 104 is mounted to the rear body 103. The problem of proper alignment and adjustment of camera body portions to produce dimensional accuracy by adjustments and the like are necessary in the manufacturing process of such multi-part camera bodies so that the distance between the mount surface and the film surface are made constant. Moreover, the problems addressed here are compounded in situations where repairs and the like necessitate separation and reassembly of the rear body 103 and the front body 104. In particular, repairs and the like often required operations that call for high accuracy settings similar to those done during original manufacture in order to provide dimensional accuracy so that the distance between the mount surface and the rail surface is kept constant.
The above-mentioned problems associated with multi-part bodies are solved by the present invention.
The final problem associated with prior art multi-part camera bodies which is addressed and solved by the present invention, is also illustrated by FIG. 5.
In FIG. 5, after the shutter 106 is inserted into the rear body 103, a front body 104 with an integral mirror box is affixed thereto. The front body 104 is affixed to the mounting surfaces 103a of the rear body 103. Moreover, a mount 105 is affixed to the front body 104. As such, after shutter 106 is inserted into the rear body 103, the front body 104 is affixed to the rear body 103 thereby making access to shutter 106 difficult. As such, the typical camera body structure as depicted in FIG. 5 indicates that when shutter 106 has to be changed or removed, because of breakdowns and the like, such operation could not be carried out without separating the rear body 103 and front body 104.
The present invention solves the shutter access problems associated with multi-part, prior art camera bodies mentioned above.